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AFM to TB boot no port


Dave WM

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The diameter of the throttle neck is about 2 1/4" and the diameter of the AFM is about 2 5/8".  The stock connecter is a pretty snug fit.   The hose you found  go's from 2" to 3" so there would need to be a little stretching on the 2" side and some compressing on the 3" side.  

I suppose it would do if you had nothing else available as you would have to make it fit properly.  But it is not enough of a savings cost wise (about $40?) overall to justify the struggle IMO.

Edited by gwri8
spellin an phonics
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The ported version was introduced in 78 and they changed the tubing scheme to try to keep the AAR cleaner. I haven't investigated it, but I've heard that Nissan tried to update earlier years to the 78 style. Not sure if it was an official recall or just "while it was in here" kind of thing.

They probably superseded the non-ported version with the ported one.

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10 minutes ago, Captain Obvious said:

The ported version was introduced in 78 and they changed the tubing scheme to try to keep the AAR cleaner. I haven't investigated it, but I've heard that Nissan tried to update earlier years to the 78 style. Not sure if it was an official recall or just "while it was in here" kind of thing.

They probably superseded the non-ported version with the ported one.

I've wondered about this also.  I believe it was changed it in mid 77' and I think you are right about the AAR.  Maybe they had some complaints or took note of dealer repair frequency for the FI? 

My 01/77 had been reconfigured to the new boot when I found it.  But it just didn't look right to me, kinda like a wang laying across the manifold, so I routed to back to the old way and capped the boot.  I don't know if I'll run into any problems later or not.  fingers crossed :huh:.

Before and After

 

GLW6332.jpg

IMG_0678.jpg

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Oil laden air from the valve cover got sucked through the AAR and gummed it up. 

 

The hot bimetal element and an electrical short may have also presented a fire hazard if not fires. 

 

Note that the original hose from the VC to the AAR has a wire brush-thingy stuck in it (Flame Arrestor).  Have a look!

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Thanks for the explanation Blue.  Summation: Fire = bad.  Mine is not original so there is currently no flame arrestor. 

Now I have to go back to the un-asthetic garden hose look and try to make it presentable.  Maybe I can put a bow on it………...LOL

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Ok the plot thickens. This all started when I noticed my portless boot had a crimp in the accordion. It looks like it must have been installed that way and over time it took a set as it would not stay popped out when I removed it and tried. Its prob not a big deal I suppose there could be some restriction or turbulence but I doubt it. Of course OCD kicks in so it must be made right.  The search was fruitless for a un ported boot (new) and then that turns into how to make a ported boot work, bonus reduction if fire hazard. Fast forward to the score of the later model hoses and hardware.

But now a complication, I found an old ported boot, completely rotten and cracked up, but inside I notice a spring steel circle with some loops on the end (to prevent puncture I am sure) that fits inside the boot accordion. I try that in my unported boot and if fixes the crimp perfectly. Perhaps this crimp was a common problem and the spring steel circle was a later mod?  Anyway where the crimp had been I noticed some slight cracking just starting not all the way thru, more like rubber fatigue. I used some weather strip cement to coat this area, and reinstalled. So now the orig prob is fixed but I have something new to consider (the fire hazard of the orig design). I don't worry too much about that as I always have a fire extinguisher handy, but may still upgrade IF I come across a nice ported boot for a good price. In the mean time one more little detail I can check off.

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10 hours ago, Captain Obvious said:

I always thought that spring was to prevent kinking.

Why not just put on a ported boot and plug the hole. That's what I did. The OCD simply won't let you have that unused nipple sticking up in plain view?

no I was ready to give in on the ported boot with a plug until I found out it was a safety thing (I currently do NOT have the flame arrester). so then I figured if I can only get new ported boots may as well go all in and do the mod to use it.

Edited by Dave WM
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9 hours ago, gwri8 said:

The ported boots are still available new from various places.  If you are looking for a used ported one,  I have a couple.  PM me if you are interested.

yep, I am thinking about it, but my old unported boot with the spring inside is really very good. It was just the kink that was bothering me.

I will prob end up buying a new ported eventually to make use of my later model plumbing I was able to get. For now I will be looking for that flame arrester.

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I haven't read the TSB for the 78 reroute, but I thought the ported boot was a "car won't idle correctly" thing, not a fire safety thing.

If the AAR gunks up with condensation from impurity carrying blow-by gasses it might stick get sticky and not operate properly resulting in improper idling conditions. The 78 style reroute of the hoses allows the AAR to pull from further upstream than the PCV line so the air that it pulls from should be cleaner.

Both the 78 style and the earlier routing should have the spark arrester in the PCV hosing (which IS a fire thing).

I think the "AAR fire" thing was Blue's theory that (however improbable) a gunked up AAR could potentially cause an engine fire if that flammable gunk were paired with an electrical fault inside the AAR resulting in an ignition source.

ZedHead, Do you know if that TSB posted anywhere? Would be an interesting read.

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3 hours ago, Captain Obvious said:

ZedHead, Do you know if that TSB posted anywhere? Would be an interesting read.

Humble wrote about a half-page on it with lots of detail but never gave any Bulletin numbers.  Haven't found any documents.  Apparently it was an actual recall with repair kits distributed to the dealers, and stickers to place under the hood when done.  My 76 had the old hose routing and no sticker.

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It's essentially just a piece of steel wool, but more prickly and stiff.  I replaced my PCV hose with a piece of water hose 60,000 miles ago.  No arrestor and the hose is fine. I like to live on the edge though.

 I still have the old hose, hard as wood, with the arrestor inside it.  

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Almost forgot that I had gone through your search before, myself.  Part #12.  I was wrong above, it's not steel wool, it's more like a piece of gun barrel brush.  Discontinued at Courtesy.  Spelled with an "e" also.

http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-280z/emission-control-device/12

http://www.courtesyparts.com/oe-nissan/15296n4200

 

Arrester.PNG

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